Shock attenuating devices



Aug 24, 1965 w. H. TRAsK 3,202,412

SHOCK 4A'I'TENUTING DEVICES Filed March e, 1964 2 sheets-sheet 1 muy.

Aug. 24, 1965 w. H. TRASK 3,202,412

SHOCK AT'I'}U'I`II\G DEVICES med March e, 1964 2 sheets-sheet 2 INVENTOR, l/Va/a er /v Tras/ BYgM-{aumr United States Patent Oli ice 3,262,411?. SHOCK ATTENUAHNG DEVCES Walter H. Trask, Santa Clara, Calif., assigner to W. lli. Miner, Inc., Chienne, lill., a corporation ci Delaware Filed Mar. d, 1%4, Ser. N 349,546 la Claims. (Cl. 267--30 This invention relates, generally, to shock attenuating units or devices, so-called shocli absorbing mechanisms, which dissipate the energy of applied load or impact forces, and it has particular relation to shocl; absorbing units or devices for use as or in draft gears for railroad cars.

This is a modification of the invention disclosed in my co-pending application, Serial No. 7,308, filed February 8, 1960, now US. Patent No. 3,l45,535, .dat-ed May 26, 1964, the specillcation and drawings of which are incorporated herein by reference.

Shock attenuating or absorbing units as described herein employ a resilient member of a material having the property of self-restoration, namely, restoring itself to the configuration it had prior to its distortion by the application of a load force thereto, such characteristic or self-restoration being aided by the factor of securing or bonding a resilient member to a support element which -is non-extensible and non-distortable under normal or practical temperatures and pressures. The bonding of the resilient member to the support element permits the material of said member to flow, as by molecular movement, in regions thereof removed from immediate contact with the support element; upon release of the distorting force, the natural resilience or elasticity returns said member to its undistorted original position relative to the support element. Shock absorbing devices exhibiting the aforementioned characteristics of self-restoration are lnown in the art, and although generally satisfactory for certain shock absorbing applications, such devices have an un desirably high reaction force and, upon release of the distorting force, a high percentage of the energy of impact stored in the device during distortion is released in the form of recoil.

Accordingly, an object of the present invention is to provide a .shock attenuating unit employing a resilient member, such as rubber, and having decreased recoil and increased shock absorbing capacity vas compared to the use of the resilient member per se.

Another object of the present invention is to provide a new and novel shock attenua-.ting unit which is only partly formed of resilient material and which has improved operational characteristics over similar known type units formed wholly of resilient material, while preserving unchanged those desirable characteristics of such wholly resilient units including simplicity, economy, ruggedness, adaptability, etc.

Another object of the invention is to simplify the construction of a shock absorber employing hydraulic operating principles which will be more economical to manufacture than conventional hydraulic shock absorbers heretofore used.

Another object of this invention is to provide a shock attenuating unit comprising one or more non-extensible support elements bonded lto a like number of surfaces of a resilient member having a cavity or chamber containing a ilowable dampening medium whereby .the hysteresis of the unit 4as a whole is enhanced.

Still another object of this invention is to provide a shock attenuating unit or device in which the resilient member, bonded to a non-extensible support element, provides the primary if not .the sole restoring force to return a mass of pressure deformable, substantially noncompressible and non-resilient material, contained within a cavity or chamber in lthe resilient member, to its original conguration after the deforming force has been dissipated or removed.

Another more detailed object of this invention is to provide a shock attenuating unit or device of the charcter described wherein telescopically associated orifice defining means are provided in the cavity or chamber through which the flowable dampening medium is metered during compression of the unit or device whereby to improve the shock absorbing characteristics thereof.

Other objects of this invention will, in part, be obvious and appear hereinafter.

This invention is disclosed in the embodiments thereof shown in the accompanying drawings and it comprises the features of construction, combination of elements and arrangement of parts which will be cxemplied in the structures hereinafter set forth and the scope of the application as indicated in the appended claims.

For a more complete understanding of the nature and scope of this invention, reference can be had 'to the following detailed description, taken together with the accompanying drawings, in which:

FGURE l isa central vertical section through a shock attenuating unit embodying the invention taken along line lt-* of FEGURE 2;

FlGURE 2 is a composite View of the unit shown in FIGURE. l Wit-h the upper half thereof being in plan and with the lower half .thereof being in horizontal section taken along line 2-2 of FIGURE l;

FGURE 3 is a vertical central section similar to FIG- URE l with the unit shown under maximum compression;

FGURE 4 is a central vertical section similar to FlG- URE l of another unit embodying the invention; and

FlGURE 5 .is a central vertical section similar to Fit"- URES l and 4 of still another unit embodying the invention.

Referring now t-o the structural details shown in the drawings, FIGURE l shows a generally cylindrical shock attenuating pad or unit l@ embodying one form of the invention in its normal non-distorted condition and FlG- URE 3 shows the same unit in its fully stressed or distorted condition.

The unit lil comprises, in general, a unitary resilient member lll having a pair of opposite and parallel forcereceiving surfaces l2 and ld and a generally cylindrical central opening l5 which extends therethrough between the pair of force-receiving surfaces. A pair of rigid noncxtensible circular end support elements 1d and if? are bonded to the force-receiving surfaces l2 and ld, respectively, of the resilient member ll in ya manner such that same over-lie the opposite ends of the central opening l5 therein whereby to provide a closed chamber 13 within the unit lll.

. As will be described in greater detail hereinafter, the chamber l is filled with a suitable dampening medium whereby the units are characterized by substa ally improved shock attenuating properties. Although not shown in the drawings, each unit disclosed herein may be provided with means for introducing a suitable dampening medium into the closed chamber thereof, for instance, suitable openings and closures therefor.

The resilient member lll consists or rubber or rubberlike material Whereas the support elements :le and 117 are of a material, such as metal, which under normal or practical conditions is non-extensible. With this structural arrangement wherein the resilient rubber-like member ll is bonded between the pair of non-distor'rable support elements le and l?, data points are provided to which the rubber-like material will return after distorting forces have been removed therefrom, whereby the resilient member assumes its original conguration. Prc-- erably, as illustrated in the drawings, the support elev particularly A affect" theV normal `conically in a kments are bonded to the entire arealextent of the forceand 5, respectively, are generally circular or disc-like in configuration. It has been found that the application of compression forces in an axial direction to a generally circular shock attenuating unit, such as the unit 111 of FGURE 1, causes the rubber-like material of the resilient member 11 to flow outwardly away from the axial center thereof when the chamber 13 is filled with a iowable or deformable dampening medium. Therefore, for reasons which are believed to'be obvious, units of this type, particularly those which are to be disposed in a conining cylindrical housing, preferably have the peripheral edges of the yresilient members thereof concavely recessed, as at 19 in FGURE 1.

it has been found that when-the closed chambersY of the shock attenuating units disclosed herein are filled with a dampening medium whichis' of the iiowable type, such as a low viscosity liquid or ahighviscosity plastic solid such as asphalt or wax, that the shock attenuating characteristics ofthe unit vmay be substantially improved by providing orifice means withinthe closed chamber through which all or a portion of-the flowable dampening medium is metered during compression of the unit. The particular'shape, number and location ofthe orifice means and any sub-chambers that are formed within the Vclosed chambers may be chosen to optimize the ow characteristics of the particular dampening medium being'V used, such that its resistance to fiow or deformationy will dominate or appreciably affect the over-all resistance-tod element 16 at the same slight angle as that for therannular formation 21.

A specified spacing is provided between the telescopically associated annular formation 21 and the plug-like formation Mwhereby annular or ring-like orice means 217 isdeiined between the two formations 21 and 24 dur-V ing theifull range of compression of the unit 1t). In a unit of the Vtype illustrated in FGURES 1, 2 and 3,

wherein the telesctmically associatedY formations 21 and 2d ,are tapered,.as described, with the inner end ofthe plug-likev Vformation 24 being both larger in diameter than the support plate end thereof and smaller, by a predetermined amount, than the inner diameter of the annular formation 21 at the smallest diameter inner end thereof, the effective horizontal cross-sectional area of the annular orifice means l'increases as the two formations 21 and 24 are telescoped one into the other during distortion characteristics of theV unit as a whole, and

resistance-to-distortionV characteristics of the resilient member alone.-

The' particularshock attenuatingV unit 10 illustrated in f FIGURES 1-3 isprovided with teleseopically associatedV means within the closed; chamber 13' which'dene an annular orifice 27,1: the area of which increases as the Vunit 161 is compressed! More specically, the support element 17 is provided on its inner surface withv an annular formation'Zl which is centered thereon and which Yis integral or rigid therewith.V The annular formation 21, which has an outer diameter which is approximately equal .tothe diameter of. the cylindrical'op'ening 15 in the resilient member 11, extends inwardly of the chamber 13a distance which is approximately equal to one-half' the distance betweenV the support elements 16 and 17 thereon.

when the unit 1t) Vis in its normal non-compressed conditionj .For a purpose which will be explained hereinafter, the'inner lsurface 22 of the annular formation 21 is Vtapered at a slight angle whereby same converges direction away from the support element' The shock attenuating unit 163 is further characterized by a centrally located generally cylindrical Vplug-'like formation 24Y which projectsY inwardly from the center of the inner face of the support element 16; being integral or rigid therewith, into slight or initial telescopic relationshipfwithin the annular formation 21'. As best illustrated in FIGURE 1, Vwhen the' shock attenuatingV unit 1t) is in its normal non-stressed condition, the pluglike formation dV projects inwardly'of the chamber 13 a distance which is slightiyl greater than one-half the distance between the two Vend support elements 16 and 17 wherebyV the-end 'of the formation 24 is disposed iust within the generally conical recess defined bythe inner surface 22 of the annular formation 21. The outerY verges yconically in a direction awayv from the support compression Vof the physical characteristic of the shock attenuating unit 10 may best be seen hy a comparison of FIGURES 1 and 3. lf the surfaces 22 and 25 of the formations Z1 and 24,

respectively, were not tapered, the effective orifice area,

chambers 36 andSZ being interconnected by the annularV orifice means 27. The sub-chambers 3i) and 3?) are filled with a vsuitable iiowable dampening medium ofV the character previously described herein. Thus,rwhen generally axial compression forces are exerted on the shock attenuating unit 1d, the owable dampening medium in the sub-chamber .i2-,is metered through the'orice means 27 into the sub-chamber Sii `and from there into an auxiliaryV chamber or sub-chamber 3d of annular configuration which is formed outwardly of the annular formation 21 as a result ofV radial outward Vdistortion or bulging of the resilient member as compression forces are exerted In the shock attenuating unit 1t) wherein the effect-ive area of the orifice :means 27 increases as the unit is compressed, the Vresistance tothe compression forces resulting vfrom the metering of the dampeningV medium ,decreases'as the unit is compressed.V

By varying the design ofV the specific oriiice defining? means in a particular unit, the operational characteristicsy shock attenuating units 36 and 38 wherein the resistance offeredV to compression forces applied thereto increases during closure-of the unit as a result of decreasing orifice areas are illustrated-in FIGURES 4 'and j, respectively.

As previously described in connection with the form of ,the invention illustrated in riGUrtn-s' 1, 2 and 3, the

shock attenuating units 36 and 3S illustrated in FXGURES 4 and 5 each include a unitary resilient member having av Y p air ofopposite parallely force-receiving surfaces and a generally cylindrical central opening lextending therelresilient'men'lber and overlying Vthe opposite ends of theV through, a pair of' non-extensible end support elements each bonded to one. of the force-receiving surfacesof the central opening therein toprovide a closed chamber, and

" itelescopically,associated orifice defining means'within the chamber, eachichamber being filled with a suitablecrlowable dampening medium. 7

More specifically, the shock attenuatiug unitV 36 vof FIGURE. 4 includes, a generally cylindrical resilient ,mem-

' ber d which ischaracterized bya'pair of opposite parallel force-receiving surfaces Zand 43, by acylindrical central.

,opening 144 extending therethrough, and by anY outer shock attenuating unit 1d. This 5 periphery which is recessed as at 4S, and a pair of nonextensible end support elements 46 and i7 bonded respectively to the torce-receiving surfaces l2 and i3 and overlying the ends or" the opening 44 whereby to define a closed chamber 4S within the unit 36 which is lled with a suitable llowable dampening medium.

rthe orifice defining means of the shock attenuating unit 36 or FIGURE- 4 includes a pair or telescopically associated tubular members Sil and 52 which are centered on the inner surfaces of the support elements 45 and d'7, respectively, and are disposed within the chamber 4S. The tubular members 5u and 52 are rigid with their associated support elements and, as illustrated, may be integral therewith. The outer tubular member has an outer diameter which is approximately equal to the diameter of the opening t4 in the resilient member di) with the inner tubular member 52 having a sliding fit in the outer member 5i) whereby annular orifice means of the character provided in the shock attenuating unit lill of FGURES l, 2 and 3 is not defined therebetween.

To provide suitable oriice means, the outer tubular member Si) is provided with a iirst series of circumferentially spaced transverse oriice passages 53 which are spaced a relatively short distance from the support element lid and a second series of circumferentially spaced transverse orifice passages which are spaced a greater distance from the support element de. Likewise, the inner tubular member 52 is provided with a rst series of circumterentially spaced transverse oriiice passages 5S which are spaced a relatively short distance from the support element 47 and a second series of circumterentially spaced transverse oriice passages 56 which are spaced a greater distance from the support element 47.

During compression of the unit 36, the flowable dampening medium filling the chamber 5S is metered through the several series of orifice passages into an annular auxiliary chamber or sub-chamber (not shown) which is formed outwardly of the tubular members Sill and 52, as a result of radial outward distortion or bulging of the resilient member dit as same is compressed. rlie auxiliary chamber would be similar to the auxiliary chamber 3d of the unit lil as shown in PEG-URE 3. The resistance to closing uttered by the unit 36 increases with the physical compression or distortion thereof as certain of the series of orifice passages are closed in sequence With the effective orifice area being progressively reduced as a result thereof. More speciically, as closure or compression of the unit 36 progresses and the tubular members Sil and 52 are .telescoped together, the iirst series of orifice passages lto be closed are passages Se after which passages 5a, 55 and 53 are in turn closed. When the unit 36 is fully compressed, all ot the orilice passages are closed and the end of the outer tubular member abuis against the inner surface ofthe support element 47.

The unit 35 of FEGURE 5 includes a generally cylindrical unitary resilient member 5d which is characterized by a pair of opposite parallel force-receiving surfaces 59 and titl, by a cylindrical central opening el. extending therethrough, and by an outer periphery which is recessed as at 65, and a pair of non-extensible end support elements el?. and 63 bonded to the force-receiving surfaces 59 and ed, respectively, and overlying the opposite ends of the opening el whereby to define a closed chamber 6d which is filled with a suitable owable dampening medium.

The orifice deiining means of the unit 33 of FGURE 5 comprises a pair of telescopically associated generally tubular members 67 and 6% which are centered on the inner surfaces of the support elements 62 and 63, respectively, and are disposed within the chamber ed. rthe generally tubular members 67 and 59 are rigid with their associated support elements and, as illustrated, may be integral therewith. The outer diameter of the outer tubular member 67 is approximately equal to the diameter oi the ope.....g in the resilient member g3 and the sliding lit of the inner generally tubular member 69 within the outer tubular member 67 is such that no annular orifice means of the type provided in the shock attenuating unit ld illustrated in FlGURES l, 2 and 3 is defined between the generally tubular members 67 and 653.

However, as illustrated, the inner generally tubular member 69 has a saw-toothed coniiguration inasmuch as same is provided with a series ot circumierentially arranged longitudinally extending V-shaped slots 7l which terminate at the inner surface of the support element 63. The portions of the vf-shaped slots 7l not covered by the outer tubular member 67 deiine triangular-shaped ortlice openings 73 through which the owable dampening medium is metered during compression of the unit The ellective orifice area 0i the slots 7l decreases as the generally tubular members 67 and 69 are telescoped together during compression of the shock attenuating unit 3S with the -units resistance to compression or closure increasing as a result thereof. During compression ot the unit 3d, the tlowable dampening medium is metered through the orilice slots il into an annular auxiliary chamber or sub-chamber (not shown but simiiar tothe chamber 3d of FIGURE 3) which is formed outwardly of the tubular members e7 and 69 as a result ot radial outward distortion or bulging of the resilient member 5S as same is compressed. lt is noted that the longitudinal slots ill could be other than V-shaped. For instance, they could be elongated slots of uniform width throughout their length.

From the foregoing descriptions of three specific forms or embodiments of the invention, it will be appreciated that the objects of the invention are attained, in brief, by forming a chamber within a resilient rubber-like member or pad, by providing suitable orifice dening means within the chamber, and by filling the chamber with a dov/able damp-suing medium or material of the type which is substantially non-compressible and which enmasse has little or no resiliency. Upon the application o compressive distorting load forces to the units illustiated and described herein, portions of the forces are transmitted into the resilient material for storage therein with the balance thereof being transmitted into the dampening medium to be expended or attenuated therein and transformed into heat energy as a result of the dampening medium being metered through the various orice means provided and as a result of molecular friction or cohesion. The distorted or fully compressed shock attenuating umts are returned to their unstressed or normal configurations after removal or dissipation of the impact or distorting force solely by the resilient member thereof without undesirable recoil action inasmuch as the dampening medium is again metered through the orice means provided within the closed chamber. The shock attenuating units described herein have much greater perormance characteristics than conventional all-rubber units or coil spring units as a result of the hereindescribed tructural modifications which while improving the per- `Iormance have preserved the desirable properties of conventional all-rubber shock attenuating units such as simplicity, economy, ruggedness, adaptability, etc.

Although not illustrated in the drawings, it is noted that the shock attenuating units disclosed herein may be used in various stacked arrangements so as to obtain the desirable performance characteristics for a specific installation.

lt is apparent from the foregoing description that many additional variations may be utilized in the manufacture ot shock attcnuating units according to the invention. Also new synthetic materials are constantly being developed and made commercially available, many of which undoubtedly will be found adaptable either as iiowable dampening mediums or as resilient members for such units. The invention lies in the physical relation or mechanical correlation of' suitable components, and their individual composition is important only in the sense that the individual properties of the elements of any rnechanical assemblage are important to their proper combination and co-action. One skilled in the art will know or may deduce with confidence from his own knowledge the applicabilty of available materials to the purposes of the invention, and in the case of novel materials, routine tests not of an inventive nature will provide reliable data. It is intended, therefore, that all matters shown in the accompanying drawings and described hereinbefore shall be interpreted as illustrative and not in a limiting sense.

Y l claim:

1. A compressible shock attenuating unit comprising, a unitary resilient member having a pair of opposite and parallel force-receiving surfaces and a generally cylindrical central opening extending therethrough between said pair of force-receiving surfaces, a pair of non-extensible support elements each bonded to one of said force-receiving surfaces and overlying the opposite ends of said central opening to provide a closed chamber, the wall portion of said resilient member intermediate said bonded force-receiving surfaces being distortable radially out- Vwardly upon movement of said non-extensible support elements toward one another upon the application of compression forces to the unit, separate means fixedly associated with each one of said pair of support `elements and extending inwardly of said chamber with said means serving to divide said chamber into at least two parts, a flowable dampening medium filling both parts of said chamber, and orifice means defined between said two parts of said chamber by said separate means fixedly associated with said support elements, the volumes of said two parts of said Vchamber being varied during compression of said unit and Vmovement of said separate means fixedly associated with said ysupport elements toward onew another with one part of said chamber decreasing in volume and the other part increasing inl volume and with said dampening medium being metered through said orifice means between said two parts of Vsaid chamber from the part which decreases in volume to the part which increases in volume, whereby to attenuate compressive shock forces applied to said unit.v

2. A compressible shock attenuating unit as recited in Vclaim 1 wherein said orifice defining means fixedly associated with said support elements are telescopically associated for movement relative to one another during compression of said unit.

3. A compressible shock attenuating unit as recited in claim 1 wherein the arrangement of said orifice defining means is such that the area of said orifice means decreases during compression of said unit.

4. A compressible shock attenuating unitras recited in claim 1 wherein the arrangement of said orifice defining means is such that the area of said orifice means increases during compression of said unit. Y

5. A compressible shock attenuating unit as recited in claim 1 wherein said orifice defining means comprises a pair of telescopically associated members centered one each on the inner surfaces of said pair of support elements and disposed within said closed chamber, the outer f peripheral surface of the inner one of said telescopically associated members being spaced inwardly of the inner surface of the outer one of said memberswhereby to define annular orifice means therebetween during compression of said unit and the resulting relative telescopic` sacaste a tive orifice area is decreased during compression of said unit. Y

7. ,A` compressible shock attenuating unit as recited in claim 1 wherein Said orifice defining means comprises a pairVV of telescopically associated generally tubular members centered one each on the inner surfaces of said pair vclaim ll wherein said orifice defining means comprises a pair of telescopically associated generally tubular members centered one each on the inner surfaces of said pair of support elements and disposed within said closed chamber, one of said generally tubular Vmembers having circumferentially spaced longitudinally extending V-shaped slots formed therein and terminating at the support element associated therewith whereby to define a saw-tooth configuration, said Veshaped slots defining vorifice means the area'of which is progressively decreased as said tubular members are telescoped one into the other during compression of said unit.

V9. A compressibleV shock attenuating unit comprising, a unitary resilient member having a pair of opposite and parallel force-receiving Vsurfaces and a generally cylindrical central opening extending therethrough between said` pair of force-receiving surfaces, a pair of non-extensible support elements each bonded to one of said force-receiving surfaces and overlying theopposite ends of said cen- V tral opening to provide a closed chamber, an annular member .on one of Vsaid support elements and a complementary plug-like member on the other support element, said complementary members being disposed within said chamber in a manner defining two sub-chambers and orifice means extending therebetween, and a flowy able dampening medium filling said subachambers, which drampening medium, upon compression of said unit, is metered from one of said sub-chambers through said orifice means into the other sub-chamber and then into an auxiliary chamber formed outwardly of said complementary members as a result of radial outward distortion of said compressed resilient member.

11i. A compressible shock attenuating unit comprising, a unitary resilient member having a pair of opposite and parallel force-receiving surfaces and a generally cylindrical central opening extending therethrough between said pair of force-receiving surfaces, a pair of non-extensible support elements each bonded to one of said force-receiving surfaces and overlying the opposite ends of said central opening to provide a closed chamber, a pair of telescopically associated tubular members disposed in said chamber with each being associated with and movable with a different one of said support elements, Ythe kouter one of said members ,being disposed against the inner surface of said resilient member defining said opening therethrough, a plurality of Vtransverse orifice passages formed in each of said tubular members in a manner such that as said members are telescoped together during compression of said unit each of said orifice passages is closed-'in turn with all of said passages being closed at full closure kof said unit, and a fiowable dampening medium fillingvthe spaces defined in said closed chamber by said pair of tubular members and said support elements, which dampening medium, upon compression of said unit, is metered through said orifice passages into an auxiliary chamber Vformed outwardly of said tubular members as a result of radial outward distortion of said compressed resilient member. Y

11. A compressible shock attenuating unit comprismg, a unitary resilient memberV having a pair of opposite and parallel force-receiving surfaces Vand a generally cylindrical central opening extending therethrough between said pair of force-receiving surfaces, a pair of non-extensible support elements each bonded to one of said force-receiving surfaces and overlying the opposite ends of said central opening to provide a closed chamber, a pair of telescopically associated generally tubular members disposed in said chamber with each being associated with and movable with a different one of said support elements, the outer one of said members being disposed against the inner surface of said resilient member defining said opening therethrough, said inner tubular member having a saw-tooth configuration detined by a series of circumferentially spaced longitudinal V-shaped slots formed therein, which slots terminate at the support element associated therewith and define orifice means the area of which is progressively decreased as said outer tubular member is telescoped over said inner V-slotted tubular member during compression of said unit, and a owable dampening medium filling the spaces dened in said closed chamber by said pair of generally tubular members and said sup port elements, which dampening medium, upon compression of said unit, is metered through said oriiice means into an auxiliary chamber formed outwardly of said generally tubular members as a result of radial outward distortion of said compressed resilient member.

12. A compressible shock attenuating unit comprising, a unitary resilient member having a pair of opposite parallel force-receiving surfaces and a generally cy1indri cal central opening extending therethrough between said pair of force-receiving surfaces, a pair of non-extensible elements each bonded to one of said force-receiving sur faces and overlying the opposite ends of said central opening to provide a closed chamber, an annular formation disposed on the inner surface of one of said support elements and extending inwardly of said chamber, the outer diameter of said annular formation being approximately equal to the diameter of said chamber, a centrally located generally cylindrical plug-like formation projecting inwardly from the inner face of said other support element into initial telescopic relationship in said annular formation when said unit is in a non-compressed condition, whereby said telescopically related formations divide said closed chamber into a generally cylindrical sub-chamber adjacent said one support element and an annular subcliamber adjacent said other support element, the outer diameter of said plug-like formation being less than the inner diameter of said annular formation whereby to define annular orifice means interconnecting said two subchambers, and a iiowable dampening medium filling said sub-chambers, which dampening medium, upon compression of said unit and telescopic movement of said plug like formation into said annular formation, is metered from said generally cylindrical sub-chamber through said annular orifice means and from said annular sub-chamber into an auxiliary chamber of annular configuration which is formed outwardly of said annular formation as a result of radial outward distortion of said compressed resilient member.

13. A compressible shock attenuating unit as recited in claim 12 wherein said telescopically related formations are tapered in a manner such that the area of said annular orifice means increases progressively with compression of said unit.

14. A compressible shock attenuating unit as recited in claim 12 wherein the inner surface of said annular formation converges conically in a direction away from said one support element at a slight angle and wherein the outer surface of said plug-like formation diverges conically in a direction away from said other support element at said same slight angle, whereby the radial dimension of said annular orifice means is progressively increased during compression of said unit.

References Cited bythe Examiner UNITED STATES PATENTS 949,83 3 2/ l0 Mueller. 1,067,130 7/13 Newell. 1,320,060 10/ 19 Jenney. 1,792,160 2/31 Granges. 2,262,823 llt/4l Stearns. 2,535,080 12/50 Lee 248-358 2,818,249 12/ 57 Boschi 267-33 3,027,152 3/ 62 Deschner 267-1 ARTHUR L. LA POINT, Primary Examiner. 

1. A COMPRESSIBLE SHOCK ATTENUATING UNIT COMPRISING, A UNITARY RESILIENT MEMBER HAVING A PAIR OF OPPOSITE AND PARALLEL FORCE-RECEIVING SURFACES AND A GENERALLY CYLINDRICAL CENTRAL OPENING EXTENDING THERETHROUGH BETWEEN SAID PAIR OF FORCE-RECEIVING SURFACES, A PAIR OF NON-EXTENSIBLE SUPPORT ELEMENTS EACH BONDED TO ONE OF SAID FORCE-RECEIVING SURFACES AND OVERLYING THE OPPOSITE ENDS OF SAID CENTRAL OPENING TO PROVIDE A CLOSED CHAMBER, THE WALL PORTION OF SAID RESILIENT MEMBER INTERMEDIATE SAID BONDED FORCE-RECEIVING SURFACES BEING DISTOROTABLE RADIALLY OUTWARDLY UPON MOVEMENT OF SAID NON-EXTENSIBLE SUPPORT ELEMENTS TOWARD ONE ANOTHER UPON THE APPLICATION OF COMPRESSION FORCES TO THE UNIT, SEPARATE MEANS FIXEDLY ASSOCIATED WITH EACH ONE OF SAID PAIR OF SUPPORT ELEMENTS AND EXTENDING INWARDLY OF SAID CHAMBER WITH SAID MEANS SERVING TO DIVIDE SAID CHAMBER INTO AT LEAST TWO PARTS, A FLOWABLE DAMPENING MEDIUM FILLING BOTH PARTS OF SAID CHAMBER, AND ORIFICE MEANS DEFINED BETWEEN SAID TWO PARTS OF SID CHAMBER BY SAID SEPARATE MEANS FIXEDLY ASSOCIATED WITH SAID SUPPORT ELEMENTS, THE VOLUMES OF SAID TWO PARTS OF SAID CHAMBER BEING VARIED DURING COMPRESSION OF SIAD UNIT AND MOVEMENT OF SAID SEPARATE MEANS FIXEDLY ASSOCIATED WITH SAID SUPPORT ELEMENTS TOWARD ONE ANOTHER WITH ONE PART OF SEAID CHAMBER DECREASING IN VOLUME AND THE OTHER PART INCREASING IN VOLUME AND WITH SAID DAMPENING MEDIUM BEING METERED THROUGH SAID ORIFICE MEANS BETWEEN SAID TWO PARTS OF SAID CHAMBER FROM THE PART WHICH DECREASES IN VOLUME TO THE PART WHICH INCREASES IN VOLUME, WHEREBY TO ATTENUATE COMPRESSIVE SHOCK FORCES APPLIED TO SAID UNIT. 